An evaluation of retrieval effectiveness for a full-text document-retrieval system
Communications of the ACM
A Model for Performance Evaluation of Interactive Systems
HICSS '98 Proceedings of the Thirty-First Annual Hawaii International Conference on System Sciences-Volume 4 - Volume 4
The project scheduling problem with irregular starting time costs
Operations Research Letters
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An activity network with returning loop activities has a wide variety of applications, but can cause a heavy computational burden for large networks. Moreover, if an activity processing time and/or the probability of taking a particular activity changes when the number of activity visits is added, the computation is very complicated and difficult. We propose a simulation approach to deal with stochastic activity networks consisting of multiple terminal nodes, no limit on looping activities, non-constant activity selection probabilities, and non-deterministic activity times following arbitrary distributions. Probability and time control functions are introduced to reflect the acceleration, or learning effect, of repeated activities. Performance measures such as system success/failure probabilities, time to completion/success/failure times, time between success/failure, and the pth percentile times of a project are obtained. A series of sensitivity analysis was performed to understand the trend and behavior of system performance. A cost function is developed to find an optimal strategy by manipulating control factors. To illustrate the efficacy of this simulation approach a new drug discovery and development project was analyzed. The Promodel simulation language was used for performance evaluations, and the SimRunner optimization tool for obtaining the optimal solution.